Your right Ralph.They usually catch fire cause a brake has seized up and craetes so much heat that the brake drum and rim gets soooo hot that it starts the rubber on fire.usually by the time you get there to apply water the tires on that azle have popped but there are other axles near by that might be at the bursting point and I don't know for sure but most people that are driving down highways have seen those big hunks of rubber on the side of the road,those are what might come at you and I don't think you want to take one of them in the head.You also have to take a look at what trailer he has on,i.e. flat bed or van and what his cargo is.If the flames are big enough and have been going long enough because sometimes they don't know cause the fire could be at the rear axle 48 ft back on the inside and it may heat the floor and catch the contents on fire.And ya just never know what is in a van trailer.Just be careful on your approach try and put an axle that has the blown tires on it between you and the axle that doesn't have blown tires to minimize your flying hunks of rubber hitting you.And after it's out check the load but make sure you know what he is hauling before you pop the back doors!!
During my 38-year career, I have to be honest, I never used a dry-chem on a vehicle brake fire. My fire station and response district includes 35 miles of coastline freeway, and about 30 miles of mountain roads that have provided me with a ton of MVA and vehicle fires.
Why no dry-chem? First off, it's an expensive option and it takes the dry-chem off the rig for something that would only work with a dry-chem extinguisher. We have a lot of brush and weeds along the highway, which has always presented grass/brush fire hazards in addition to the brake fire. Water works, and pretty damn good at that. I don't care about the brakes, the axle, damaging things from using water to cool the metal, etc.
With that said, if the fire gets into the cargo area, and especially if it is a hazardous material, caution must always be used when using water because of run-off potential, which means that you are extending the boundaries of the incident. Dry-chem is indicated in this type of incident, which is all the more reason to not use water as the primary extinguishing agent. Save your dry-chem for situations like this...
I care about preventing the brake fire from communicating with whatever is in the vehicle and preventing extension into the brush. I also like to minimize cleanup, get the damn fire out, get the information and get off the highway asap.
If the vehicle carries an expensive payload, or if it is a speciality vehicle like a large heavy equipment vehicle, it's not uncommon to have built in fire suppression systems because of the cost of these specialized vehicles, which dumps dry-chem on the engine compartment, axles, etc.
What they don't want is this...
In these times of fiscal restraint and lack of funding, using a dry-chem as a fire line of defense is an expensive option that can be handled using water.
if you have this kind of exchange available then maybe I'd use dry-chem as a first line of defense... for us, it's always a cost thing associated with having to get the extinguisher re-charged, leaving us in a situation where we may not be able to mitigate something more serious.
When we have a semi truck with burning tires due to hot brakes, we approach from the rear of the tractor (perpendicular to the axles) and foam the burning tires, once the flames are out we wait several minutes and then cool the axle with water.
We get them fairly often at the local truck stops.
We also have semi truck fires caused by overheating belts in Reefer units, such as this tomato truck fire we had a couple weeks ago.
Ralph auto cast is a very strong metal and does not explode like regular cast.There is always exceptions in the case but it would have to be a bad casting or a bad batch of metal to create this hazzard.But i'm pretty sure that you would not have to worry about steel shrapnel when hitting it with water.I could be wrong but Ive never seen a brake rotor or drum explode,I've seen them get hairline cracks but never explode."Gators" is my concern at one of these.
The metal parts such as the brakes, or drums will not "explode" when you hit them with water. Another problem common with these fires is the axle grease catching on fire. All of the brake parts get superheated and the inner and/or outer wheel seal fails and the grease seeps out, gets heated and starts fire. When you hit the burning grease with water you will most likely get a splattering effect, that can sometimes be dramatic. As far as a tire exploding, I've driven tractor-trailer for 16 years and have had my share of blowouts. All the way from just leaving a "gator" in the road to having said "gator" land in the back seat of a minivan that was next to me when one blew out. Fortunatley there was no child in the car seat that the tread landed in. If the air is already out of it, you don't have to worry about that one blowing out. However, be very cautious of the other tires near the burning tire, as they could blow out if they are still holding air. Recommended approach, from the sides. Be on the lookout for extension into the trailer, or cab of the truck. Be ready to use a ton of water to extinguish. Hope this helps.
Assess the situation has the fire breached the cargo area if it has you may have a hazmat situation depending on the cargo being carried you need to get the shipping docs and talk to the driver if this is the case. If it’s safe to do so approach with a hand line use foam to minimize the water you’re going to need ( foam is 5 times more effective than water alone) I am a firm believer in foam we attack ever vehicle fire with foam you get a much faster extinguishment of the fire and you conserve you water which may be a very valuable resource when you’re on the high way and don’t have a water supply nearby. Always always use proper PPE scaba, shields down, two firefighters on the hand line you should have two hand lines on the go is possible Get in get out go home !
Size-up the situation as you would anything else. Youu must learn the contents of the truck, the cargo, etc. If your dealing with over-heated brakes, you can place a PPV fan 10' or so, and begin to cool them down. Precautionary hose-line stretch, and dry chem is an option.